Ion implantation is a process for introducing dopants, additives, or impurities into a substrate via bombardment. Known ion implantation systems or apparatus may comprise an ion source and a series of beam-line components. The ion source may comprise a chamber where desired ions are generated. The ion source may also comprise a power source and an extraction electrode assembly disposed near the chamber. The beam-line components, may include, for example, a mass analyzer, a first acceleration or deceleration stage, a collimator, and a second acceleration or deceleration stage.
In known ion implanters, a final deceleration stage may decelerate an ion beam as well as shape the ion beam and change the direction of propagation of the ion beam before impacting the substrate. A deceleration stage may be designed as an electrode system having a plurality of electrodes where different voltages are applied to guide the ion beam, shape the ion beam, and decelerate the ion beam, before exiting the deceleration stage. In known deceleration stages, the beam may be guided between opposing pairs of electrodes that define a gap region where the ion beam may propagate while not striking the electrodes. For low energy ion beams, the beam height of the ion beam in a direction perpendicular to the direction of propagation tends to be greater. Thus, in known ion implanters, a deceleration stage may be designed with a gap between opposing electrodes that is adequate to accommodate a beam height for a lowest ion energy to be employed in the ion implanter.
Because the gap between electrodes may be designed for a lowest energy ion beam, for ion beams having a higher energy, the ion beam may proceed through a deceleration stage and in particular through a pair of exit electrodes, where the ion beam is spaced apart from the opposing electrodes. This configuration may lead to non-ideal results, including a lower beam current to deliver to a substrate for a given beam height.
With respect to these and other considerations, the present disclosure is provided.